Cheap CRD Intake Air Pressure sensor connector replacement
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Author:  casm [ Fri Sep 18, 2020 10:11 pm ]
Post subject:  Cheap CRD Intake Air Pressure sensor connector replacement

After 15 years of exposure to heat and vibration, the wiring connector to the Intake Air Pressure sensor (the one located on the airbox; sometimes called the 'Mercedes Sensor') in our CRD was disintegrating. This lead to the sensor becoming disconnected from its wiring, which in turn would make it impossible for the ECU to read it. When this happens, the Jeep goes into limp mode, which is not something you want to experience at 75mph on the Interstate while overtaking a semi. Trust me on that one.

Some poking around turned up two viable replacement options: Chrysler part number 68032284AA, which included a wiring pigtail along with the connector. That would have worked, but finding that it was priced in the $40-$50 range before tax or shipping seemed excessive, particularly given that the wiring to the sensor was OK. Digging a bit deeper, Mercedes-Benz part number 210-540-21-81 was found to be the exact replacement for the connector, did not include the wiring, and was pricing out at about $9.50 shipped.

Both connectors were listed in various places as being for a siren. Disregard that; as long as your sensor is OEM (or the aftermarket equivalent) and the part number for the connector is correct, this connector should fit the sensor.

A word of caution: performing this repair carries risks of damaging or destroying the IAP sensor and / or ECM, as well as having the potential for starting an electrical fire. If you're not comfortable with these risks, don't attempt the repair. You perform this at your own risk, and accept any and all liability arising from doing so. Note the multiple uses of variations of the word 'risk' in the preceding sentences; in case it wasn't clear by now, those words are there for a reason. Please heed them.

With that out of the way, replacement is pretty straightforward, provided that you know the secret of getting the connector apart without breaking it. A very small flat-bladed screwdriver is likely to be the only tool you need, but it may help to have some picks or other small poking tools laying around.

For reference, here's a photo of the get-me-home zip-tie fix that I did. It's hard to tell, but the tab that locks the connector to the sensor is broken off, allowing the sensor to become disconnected from the ECU:


Here's what its replacement looks like. Take note of the Connector Assembly Locking Tab and the Wire Numbers:


Carefully slide your very small flathead screwdriver under the Connector Assembly Locking Tab and lever it gently upwards (you do not want to break this tab) while pressing against the three empty pin sockets. This should allow the actual connector to be extracted from the assembly. Note the grey pin cover on the top of the connector:


Next, turn the connector onto its side and locate the locking tabs for the pin cover. There's one on each side:


Carefully push the locking tabs towards the pin cover. This will take some gentle wrangling, so do your best to not damage or break them. Eventually, it should be possible to remove the grey pin cover:


And that's it - you now know how to take apart both connector assemblies. Assuming that you also removed the blue seal around the connector (not necessary, but shown for completeness), you should now have the following parts sitting in front of you:


Now to deal with the KJ side of things. Bring your disassembled connector with you; it'll be needed fairly soon.

Disconnect the battery before starting in on the repair. If you recall the earlier points regarding risks, doing so will help to reduce said risks.

First things first: unplug the connector at the sensor (assuming it's still attached) and label the wires coming out of it. Use the same numbering scheme on the labels as is assigned to each wire on the back of the connector. Whatever you do, triple-check to make sure that each wire is labelled correctly:


Once that's out of the way, go ahead and disassemble the connector the same way as you disassembled the new one. When you reach the point where the grey pin cover has been removed, take note of this photo:


Photos end here; there aren't really any to include since most of the rest of the steps are reassembly.

Look at the three flat pins with arrows on them that were under the grey pin cover. With your very small flathead screwdriver, press down on the arrows while simultaneously pulling the corresponding wire from the rear of the connector. Use only as much force as is necessary to do this - you don't want to break a wire, and particularly not if it might leave a pin lodged in the connector. That would make for a Bad Day.

Note: the wires have cylindrical seals (similar to the blue one on the connector) on them. This will make them a bit difficult to remove. Just work at them carefully while pushing down on the pin and they should come out.

Once all of the wires are free, remove and discard the outer part of the old connector assembly, which has likely slid down the wires by this time.

Pull the wires through the outer part of the new connector assembly, bringing them through the smaller end. Let it slide down the wires and be out of the way for now.

Now you're going to pin the new connector. Take a wire - I'd recommend either #1 or #3 to start with - and insert its pin into the corresponding hole on the new connector. Push it in until you can feel a light click as it snaps into place, and make sure that the seal on the wire has gone into the hole without pinching or bulging. If it's not going in, don't force it - just check that the pin isn't rotated in the wiring hole and try again. Do this for all three pins.

Once all three pins are in and you're absolutely, completely, totally, entirely, 153% certain that each wire has been inserted into the correct position on the connector and the pins are snapped in place and not going anywhere, go ahead and reassemble the new connector assembly. When that's complete, plug the connector assembly back onto the sensor.

Reconnect the battery. Carefully start the KJ, checking for any signs of smoke, fire, etc. from around the connector. If you get a MIL that wasn't there before, pull the codes and check over your work if anything related to the IAP sensor is found.

Other than that, give it a test drive, and enjoy knowing that the zip-tie is no longer likely to fall off at the most inconvenient time possible :mrgreen:

Author:  PZKW108 [ Sun Sep 20, 2020 8:18 pm ]
Post subject:  Re: Cheap CRD Intake Air Pressure sensor connector replaceme

I don't have this sensor on my jeep for a long time......!

Seem like a lot of work to replace a useless part.

Author:  flash7210 [ Sun Sep 20, 2020 8:27 pm ]
Post subject:  Re: Cheap CRD Intake Air Pressure sensor connector replaceme

PZKW108 wrote:
I don't have this sensor on my jeep for a long time......!

Seem like a lot of work to replace a useless part.

If you have the GDE tune you don’t need this sensor.
If you don’t then the engine will have reduced power if this sensor is unplugged.
It’s not quite like limp mode but it’s very noticeable.

Author:  thesameguy [ Thu Sep 24, 2020 6:36 pm ]
Post subject:  Re: Cheap CRD Intake Air Pressure sensor connector replaceme

In case this comes up, I believe many of the connectors on the CRD are from TE's Micro Quadlok System (MQS) line. Pretty sure this MAP sensor connector is one of them.

TE's housings typically come in a few different colors, keys and materials. Here's all the 3-circuit housings in the MQS line.

https://www.te.com/usa-en/product-CAT-M ... &instock=N

Here's the brochure on MQS, which makes it easier to understand the keys:

https://www.te.com/commerce/DocumentDel ... 1-967642-1

TE has direct links to place that sell the housings, like Mouser. They're typically $2-$3. As long as you can extract the terminals from your existing housing, you can just insert them into a new housing. :)

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